Bayes for Schizophrenics: Reasoning in Delusional Disorders

A Bayesian account of delusional disorders that is a clear ancestor of Scott's later predictive-coding/trapped-priors psychiatry. Surveys monothematic delusions (Capgras: a loved one replaced by an imposter; Fregoli; Cotard: believing oneself dead) and anosognosia, all linked to right-frontal damage. Develops the two-factor theory (Coltheart/Langdon/McKay): factor one is an abnormal perception (Capgras patients lack the skin-conductance emotional response to familiar faces), generalized by Scott into a 'Super Mind Projection Fallacy' (assume reality is such that your mental states are justified — extended to delusions of grandeur and persecution); factor two is damage to the right dorsolateral prefrontal cortex, which McKay reframes not as a general updating deficit but as a loss of the ability to use PRIORS — a 'Super Base Rate Fallacy' where only explanatory adequacy matters. This elegantly explains why delusions resist counter-evidence (the patient just elaborates the hypothesis: the imposter must be a telepathic alien) and ties to dreams (RDPC offline). Ends with honest open questions (why 'you have brain damage' doesn't dislodge it; why delusions are so specific).

Quality 79 · Excellent. Strong (top) / low-Excellent. One of the meatier, more important LW posts: a lucid synthesis of real psychiatry/neuroscience with the Bayesian-brain framework, and the seed of a major thread of Scott's later work (predictive coding, trapped priors). Held at 79 because the core two-factor/prior-deficit theory is the researchers' (Coltheart, McKay); Scott's contribution is the synthesis and the Mind-Projection/Base-Rate framing. 79.

Claude’s paradigm shift 55 · Moderate. Moderate(-upper). The Bayesian-predictive-coding account of delusion was relatively fresh circa 2012, and Scott's 'Super Mind Projection / Super Base Rate Fallacy' framing is a genuine synthesis, though built on published two-factor theory. 55.

Real-world impact 3 · Moderate. A lucid Bayesian synthesis of real psychiatry/neuroscience (Capgras, Cotard, anosognosia) and the seed of Scott's later predictive-coding / trapped-priors thread (the core two-factor theory is the researchers'). Conceptual influence within rationalist/psychiatry discourse, no material change — modest RWI.